package main

import (
	"bufio"
	"fmt"
	"io/ioutil"
	"net"
	"net/url"
	"os"
	"strconv"
	"strings"
)

// SpartanURL parses u and calls SpartanParsedURL with the parsed url
func SpartanURL(u, input string) bool {
	parsed, err := url.Parse(u)
	if err != nil {
		fmt.Println("invalid url")
		fmt.Println(err.Error())
		return false
	}
	if parsed.Host == "" {
		parsed, err = url.Parse("spartan://" + u)
		// this is repeated, ugh!
		if err != nil {
			fmt.Println("invalid url")
			fmt.Println(err.Error())
			return false
		}
	}
	if parsed.Scheme != "spartan" {
		fmt.Println("Unsupported scheme")
		return false
	}
	return SpartanParsedURL(parsed, input)
}

// SpartanParsedURL fetches u and displays the page
func SpartanParsedURL(u *url.URL, input string) bool {
	host := u.Host
	if u.Port() == "" {
		host += ":300"
	}
	// Connect to server
	conn, err := net.Dial("tcp", host)
	if err != nil {
		fmt.Println("unable to connect to " + u.Host)
		fmt.Println(err.Error())
		return false
	}
	defer conn.Close()
	// Send request
	path := u.Path
	if u.Path == "" {
		path = "/"
	}
	conn.Write([]byte(fmt.Sprintf("%s %s %d\r\n", u.Hostname(), path, len(input))))
	conn.Write([]byte(input))
	// Receive and parse response header
	reader := bufio.NewReader(conn)
	header, err := reader.ReadString(byte('\n'))
	if err != nil {
		fmt.Println("Error reading response header")
		return false
	}
	// Parse header
	statusParts := strings.SplitN(header, " ", 2)
	status, err := strconv.Atoi(statusParts[0])
	if err != nil {
		fmt.Println("invalid status code:" + statusParts[0])
		return false
	}
	meta := strings.Trim(statusParts[1], "\r\n")

	// Handle status
	switch status {
	case 2:
		// TODO: handle mime type
		bodyBytes, err := ioutil.ReadAll(reader)
		if err != nil {
			fmt.Println("Error reading body")
			return false
		}
		body := string(bodyBytes)
		fmt.Print(body)
	case 3:
		SpartanURL("spartan://"+host+meta, "")
	case 4:
		fmt.Println("Error: " + meta)
	case 5:
		fmt.Println("Server error: " + meta)
	}

	return true
}

func Usage() {
	fmt.Fprintln(os.Stderr, `
Usage: sparte [--help] [URL] [-i INPUT] [-f FILE]

	--help     usage
	-i         send INPUT to URL
	-f         send contents of FILE as input to URL (use - for reading stdin pipe)
	`)
	return
}

func main() {
	args := os.Args[1:]
	if len(args) == 0 {
		Usage()
		return
	}
	url := args[0]
	input := ""
	for i, arg := range args {
		if arg == "--help" {
			Usage()
			return
		}
		if arg == "-i" || arg == "-f" {
			if len(args) < i+2 || (i == 0 && len(args) < i+3) {
				fmt.Println("input argument or URL missing")
				return
			}
			url = args[i-1]
			if arg == "-i" {
				input = args[i+1]
				break
			}
			// arg must be -f
			file := args[i+1]
			var inputBytes []byte
			var err error
			if file == "-" {
				stat, _ := os.Stdin.Stat()
				if (stat.Mode() & os.ModeCharDevice) != 0 {
					fmt.Println("nothing in stdin")
					os.Exit(1)
				}
				inputBytes, err = ioutil.ReadAll(os.Stdin)
				if err != nil {
					fmt.Fprintln(os.Stderr, "Error reading stdin")
					os.Exit(1)
				}
			} else {
				inputBytes, err = ioutil.ReadFile(args[i+1])
				if err != nil {
					fmt.Fprintln(os.Stderr, "Error reading file")
					os.Exit(1)
				}
			}
			input = string(inputBytes)
			break
			// ignoring other args if any
		}
	}
	SpartanURL(url, input)
}